Hi there and thank you for your question. My name is Ann and I am a licensed veterinarian and I would be happy to assist you.
There are two possibilities here. The first is that he is constipated, and the second is that he has diarrhea. If you have a rubber glove and some lube, and you are willing, you can gently insert a finger all the way into his rectum. If you don't hit any feces with your finger, then the problem is diarrhea. If you do feel firm feces with the tip of your finger, he is constipated. With diarrhea, they can dribble small amounts at a time all day for multiple days. With constipation, they strain a lot and squeeze liquid feces out around the firm feces.
As long as he is eating and drinking and acting normal, here is what I would do. I would get some Metamucil (do they have that in the UK?) or other soluble fiber supplement, or else canned pumpkin (if they have that in the UK) and give him the human dose that it says on the container each day. For canned pumpkin, give a tablespoon twice daily. Fiber will help with both constipation and diarrhea. Also, I would give a tablespoon of plain yogurt twice daily, because it helps the good bacteria return to the colon, and will help with both diarrhea and constipation, too. Then I would switch back to the bland diet- boiled chicken breast or lean ground beef mixed 50/50 with white rice. It won't hurt the constipation, but may help if the problem is diarrhea.
If at any time he stops eating or starts acting lethargic, you should see a vet right away. If he is not any better by Tuesday, I would see a vet.
I hope that I have answered your question thoroughly... if you feel that I have provided anything less than excellent service, please reply to me first before rating my service and let me know how I can better assist you. Thank you for your question; it has been a pleasure being able to provide assistance. Best of luck.